Various attempts have been made to heat treat thermoplastic fabric at the loom. One such attempt is exemplified by the device illustrated in U.S. Pat. No. 2,769,222 wherein fabric to which tension has been applied is heated after it passes the take up roll utilizing a heater and reflector both positioned on one side of the fabric. U.S. Pat. No. 3,515,174 illustrates a further attempt to solve the problem utilizing a heater positioned above a take up roll which has a roughened surface for maintaining the fabric in open width against transverse shrinkage. Such devices, however, have been inadequate in so far as applying heat uniformly across both sides of the fabric and applying insufficient means for resisting lateral shrinkage of the fabric and no effort is made to remove the fumes resulting from heating the fabric to elevated temperatures.
Accordingly, it is an important object of this invention to provide apparatus and method for heat treating fabric at the loom wherein the fabric is maintained in open width resisting any tendency to shrink laterally by restraining the edges of the fabric against transverse shrinkage.
Another important object of the invention is to provide means for uniformly heating thermoplastic fabric and heat treating same at the loom by uniformly heating the fabric across both faces thereof while moving in open width at the loom.
Another important object of the invention is to exhaust fumes generated by heating fabric to elevated temperatures making possible heat treatment of fabric at the loom.